1. Technical Field
The present disclosure relates to a power supplying device, in particular, to a backup power supplying device having programmable current-balancing control.
2. Description of Related Art
Referring to FIG. 1A, FIG. 1A is a schematic diagram illustrating a conventional backup power supplying device. The backup power supplying device 1 includes more than two power modules. Taking FIG. 1A as an example of two power modules, a first power muddle 11 and a second power module 12 jointly share the output power to a load, so that when any one of the power modules is interrupted abnormally, the other power module which can operate normally may keep providing power to the load to meet the demand for uninterruptible power supply.
The backup power supplying device described as above could be in a current-balancing control state. The demand for the input power of the power supply terminal when the two power modules supply power concurrently is higher than that when only one power module is at work. Therefore, there two applications are derived. In the first application, one power module (e.g., the second power module 12) stays in a sleep mode in order to reduce power consumption. When another power module (e.g., the first power module 11) is broken, the power module staying in the sleep mode (e.g., the second power module 12) can be started to output power to the load. In the second application, the input terminal of one power module (e.g., the second power module 12) is changed to connect to a battery, in order to avoid the load failing to continue operating when the mains AC is interrupted. It is worth mentioning that when an abnormality occurs on the first power module 11, the first power module 11 can transmit an error signal PR to the second power module 12 so that the second power module 12 can be switched to a power supply mode accordingly. The two above-mentioned applications both are making the power source enter the sleep mode when the power module is in an off state. When an abnormality occurs on the power module which supplies power originally or the input power of the power module is interrupted, a problem of interruption instantaneously and restart on the output voltage will occur. At this time, it will cause the power interruption and restart on the system (or load), causing the system administrator must reset the system settings, resulting in the system operating cost increases. The following description of FIG. 1B is a clear example.
Referring to both FIG. 1A and FIG. 1B, FIG. 1B is an output voltage waveform diagram of a backup power supplying device 1 shown in FIG. 1A when an output voltage interruption occurs. The input voltage of the backup power supplying device 1 can be mains (AC), DC, or any type of input voltage. The present disclosure is not limited to the type of the input voltage and the voltage value. When an interruption occurs on a first input voltage of the first power module 11 and the voltage level is reduced to zero volts as shown in FIG. 1B, a first output voltage of the first power module 11 then drops to zero volts. The second power module 12 can receive the error signal PR from the first power module 11 to generate a second output voltage to supply power. It is worth mentioning that the second input voltage of the second power module 12 is always maintained without interruption. There will be a time for system interruption and restart on the voltage change, which is obtained from the total output terminal of the first power module 11 and the second power module 12 connected in parallel.